<VV> electrical loading questions

[Craig Nicol]

Mark asked:
Happy New Year everyone!  I have a 63 Spyder that I'm contemplating  adding
a 
electric fuel pump to.  I have always noticed that as I turn on  more 
electrical things, that my engine slows down slightly more as each item is
turned on 
while idling.  It doesn't kill the engine, but is  noticeable.  If i add an 
electric fuel pump, I really don't want to go  adjust the idle speed up.
Does 
anyone else have this problem?  What  could be the answer here?  What's the 
best way to wire a  pump?

Craig replies:
Sounds normal to me.  The power to run things comes from your generator -
the more loads you turn on, the more power it takes from the engine (to turn
the generator). This is more of a factor with bigger loads, such as the
headlights or heater.  Small loads, like a fuel pump, shouldn't affect the
idle. 

The simple way to wire it is to connect it to a wire from the fuse panel
that's switched with the ignition. 

The correct way is to install a relay that supplies fused power from the
main lead at the fuse panel. The relay is then activated by the cranking
signal and after starting is maintained by a special 3-wire oil pressure
switch. 

This arrangement only provides fuel pump power when the engine is cranking
or running. 

Craig Nicol